iio: accel: bma220: Fix buffer alignment in iio_push_to_buffers_with_timestamp()

To make code more readable, use a structure to express the channel
layout and ensure the timestamp is 8 byte aligned.

Found during an audit of all calls of this function.

Fixes: 194dc4c71413 ("iio: accel: Add triggered buffer support for BMA220")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210501170121.512209-3-jic23@kernel.org

diff --git a/drivers/iio/accel/bma220_spi.c b/drivers/iio/accel/bma220_spi.c
index 36fc987..0622c79 100644 (file)
--- a/drivers/iio/accel/bma220_spi.c
+++ b/drivers/iio/accel/bma220_spi.c
@@ -63,7 +63,11 @@ static const int bma220_scale_table[][2] = {
 struct bma220_data {
        struct spi_device *spi_device;
        struct mutex lock;
-       s8 buffer[16]; /* 3x8-bit channels + 5x8 padding + 8x8 timestamp */
+       struct {
+               s8 chans[3];
+               /* Ensure timestamp is naturally aligned. */
+               s64 timestamp __aligned(8);
+       } scan;
        u8 tx_buf[2] ____cacheline_aligned;
 };
 
@@ -94,12 +98,12 @@ static irqreturn_t bma220_trigger_handler(int irq, void *p)
 
        mutex_lock(&data->lock);
        data->tx_buf[0] = BMA220_REG_ACCEL_X | BMA220_READ_MASK;
-       ret = spi_write_then_read(spi, data->tx_buf, 1, data->buffer,
+       ret = spi_write_then_read(spi, data->tx_buf, 1, &data->scan.chans,
                                  ARRAY_SIZE(bma220_channels) - 1);
        if (ret < 0)
                goto err;
 
-       iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+       iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
                                           pf->timestamp);
 err:
        mutex_unlock(&data->lock);